This study consists of six interrelated projects which examine the regulation of synthesis and secretion of connective tissue macromolecules and the role of disordered connective tissue structure and function in disease. We will attempt to determine whether some of the products of conversion of procollagen function to control procollagen synthesis and secretion by feedback regulation and whether specific plasma membrane receptors are involved in such regulation. Intracellular events involved in the control of collagen production will be evaluated by translation of isolated collagen messenger RNA in a cellfree protein synthetic system derived from wheat embryos. We expect that cell-free protein synthesis will provide a new approach to the determination of the full extent and chemical nature of the nontriple helical sequences in procollagen. Using immunologic methods, we plan to detect and select for clones of fibroblast-like cell lines which are deficient in collagen production. Analysis of such variants should provide additional information regarding the cellular requirements for normal fibrogenesis. The nature and regulation of synthesis of matrix macromolecules by smooth muscle cells in culture will be examined and the role of altered proliferative activity and synthesis of connective tissue proteins by smooth muscle cells in the genesis of atherosclerosis will be considered. Connective tissue structure and function will also be evaluated in a wide variety of patients who either spontaneously, or as a reaction to injury, manifest disorders which suggest an underlying defect in connective tissue metabolism. Since adrenal corticosteroids have profound effects on connective tissues we plan to evaluate the effects of these hormones on the synthesis and secretion of procollagen and protein-polysaccharides by fibroblasts in culture. Attempts will be made to analyze the contribution of changes in levels of cyclic nucleotides and prostaglandins to the effects which are observed.